Abstract

We present a self-consistent field algorithm for the restricted open-shell Kohn–Sham method which can be used to calculate excited states that have the same spatial symmetry as the corresponding ground states. The method is applied to transitions in polyenes, cyanines, and protonated imines. Excitation energies obtained with gradient corrected functionals are found to be significantly redshifted; the shift is constant within a homologous series. Planar excited state geometries have been optimized for all systems.